Fish muscle tissue δ13C and δ15N values responded immediately to
the forced diet switch from chironomid larvae to feed during week 5
of the tank experiment (Fig. 2A, B). Both δ13C and δ15N values of fish
muscle tissue closely tracked those for fish in the chironomid larvaeonly
treatment during weeks 1–5, transitioned towards the feed signal
during week 6 (immediately following the diet switch), then approached
the steady-state values achieved by fish in the feed-only treatment
during weeks 7–10. Similarly, fish muscle tissue δ13C and δ15N
values in the low and high-feeding treatments of the pond experiment
tracked the values of fish in the no-feeding treatment during weeks
1–3, then transitioned towards the feed signal during week 4 (Fig. 2C,
D). In weeks 5–7, muscle tissue δ13C and δ15N values in the low and
high-feeding treatments stabilized on values intermediate to those of
fish reared in the no-feeding treatment in ponds and feed-only treatment
in tanks.